The document provides information on removing the swing reduction gear from an excavator. The key steps are: 1. Drain oil from the reduction gearbox and disconnect hydraulic and lubrication lines. 2. Remove 11 bolts holding the swing reduction gearbox and motor assembly to the frame and lift it off. 3. Disassemble the reduction gearbox by removing the sun gears, carriers, ring gear, and drive shaft. Care must be taken not to damage any parts during disassembly.

1. K1024241E Shop Manual
Copyright 2006 DOOSAN
DOOSAN reserves the right to improve our products in a continuing process to provide the best
possible product to the market place. These improvements can be implemented at any time with no
obligation to change materials on previously sold products. It is recommended that consumers
periodically contact their distributors for recent documentation on purchased equipment.
This documentation may include attachments and optional equipment that is not available in your
machine's package. Please call your distributor for additional items that you may require.
Illustrations used throughout this manual are used only as a representation of the actual piece of
equipment, and may vary from the actual item.
Shop Manual
K1024241E
Serial Number 5001 and Up
DX225NLC

2. Table of Contents
Page I
1Table of Contents
Safety
Track Excavator Safety....................................................................... SP000014
Specifications
Specification for DX225NLC ............................................................... SP001010
General Maintenance
General Maintenance Procedures ...................................................... SP000016
Standard Torques ................................................................................ SP000813
Upper Structure
Cabin .................................................................................................... SP000943
Counterweight....................................................................................... SP000940
Fuel Tank............................................................................................. SP001014
Fuel Transfer Pump ............................................................................ SP000021
Swing Bearing...................................................................................... SP001109
Swing Reduction Gear ........................................................................ SP000915
Lower Structure and
Chassis
Track Assembly ................................................................................... SP000911
Engine and Drive Train
Drive Coupling (Main Pump) .............................................................. SP001069
Hydraulics
Hydraulic System Troubleshooting, Testing and Adjustment ........... SP000913
Accumulator.......................................................................................... SP000028
Center Joint (Swivel)........................................................................... SP000029

3. Table of Contents
Page II
Cylinders............................................................................................... SP000030
Swing Motor......................................................................................... SP001013
Travel Motor......................................................................................... SP000922
Gear Pump........................................................................................... SP000931
Main Control Valve.............................................................................. SP000034
Axial Piston Pump............................................................................... SP001008
PTO Server.......................................................................................... SP000933
Remote Control Valve (Work Lever / Joystick) ................................ SP000069
Travel Control Valve (with Damper) .................................................. SP000070
Solenoid Valve Assembly.................................................................... SP000445
Breaker EPPR Valve (Opt)................................................................. SP000192
Hydraulic Schematic (DX225NLC)...................................................... SP001057
Electrical System
Electrical System ................................................................................. SP000935
Electrical Schematic (DX180LC/DX225LC/DX225NLC/DX255LC) .... SP000936
Attachments
Boom and Arm .................................................................................... SP000937
Bucket................................................................................................... SP000939

4. SP000014
Page 1
Track Excavator Safety
SP000014
TRACK EXCAVATOR SAFETYSP000014
Track
Excavator
Safety
Edition 1

5. SP000014
Page 5
Track Excavator Safety
SAFETY PRECAUTIONS
APPLICABLE MODELS
The contents of this section apply to the following models
and serial number ranges.
CAUTION!
Follow all safety recommendations and safe shop
practices outlined in the front of this manual or those
contained within this section.
Always use tools and equipment that are in good
working order.
Use lifting and hoisting equipment capable of safely
handling load.
Remember, that ultimately safety is your own personal
responsibility.
MODEL SERIAL NUMBER RANGE
DX180LC 5001 and Up
DX225LC 5001 and Up
DX225NLC 5001 and Up
DX255LC 5001 and Up
DX300L 5001 and Up
DX340LC 5001 and Up
DX420LC 5001 and Up
DX480LC 5001 and Up
DX520LC 5001 and Up

6. SP000014Track Excavator Safety
Page 6
TO THE OPERATOR OF A
DOOSAN EXCAVATOR
Please respect the importance of taking responsibility for
your own safety, and that of other people who may be
affected by your actions.
The safety information on the following pages is organized
into the following sections:
1. “General Safety Essentials” on page 1-10
2. “Location of Safety Labels” on page 1-11
3. “Summary of Safety Precautions for Lifting in Digging
Mode” on page 1-12
4. “Unauthorized Modifications” on page 1-13
5. “General Hazard Information” on page 1-13
6. “Before Starting Engine” on page 1-22
7. “Machine Operation” on page 1-26
8. “Maintenance” on page 1-33
9. “Battery” on page 1-42
10. “Towing” on page 1-44
11. “Shipping and Transportation” on page 1-45
12. “Lifting With Sling” on page 1-45
DANGER!
Unsafe use of the excavator could lead to serious injury
or death. Operating procedures, maintenance and
equipment practices or traveling or shipping methods
that do not follow the safety guidelines on the following
pages could cause serious, potentially fatal injuries or
extensive damage to the machine or nearby property.

7. SP000014
Page 7
Track Excavator Safety
WARNING!
Improper operation and maintenance of this machine
can be hazardous and could result in serious injury or
death.
Operator and maintenance personnel should read this
manual thoroughly before beginning operation or
maintenance.
Keep this manual in the storage compartment to the
rear of the operator's seat, and have all personnel
involved in working on the machine read the manual
periodically.
Some actions involved in operation and maintenance of
the machine can cause a serious accident, if they are
not done in a manner described in this manual.
The procedures and precautions given in this manual
apply only to intended uses of the machine.
If you use your machine for any unintended uses that
are not specifically prohibited, you must be sure that it
is safe for any others. In no event should you or others
engage in prohibited uses or actions as described in
this manual.
DOOSAN delivers machines that comply with all
applicable regulations and standards of the country to
which it has been shipped. If this machine has been
purchased in another country or purchased from
someone in another country, it may lack certain safety
devices and specifications that are necessary for use in
your country. If there is any question about whether
your product complies with the applicable standards and
regulations of your country, consult DOOSAN or your
DOOSAN distributor before operating the machine.

8. SP000014Track Excavator Safety
Page 8
Learn the Signal Words Used with the
Safety Alert Symbol
The words "CAUTION," "WARNING," and "DANGER" used
throughout this manual and on decals on the machine
indicate degree of risk of hazards or unsafe practices. All
three degrees of risk indicate that safety is involved.
Observe precautions indicated whenever you see the Safety
Alert "Triangle," no matter which signal word appears next to
the "Exclamation Point" symbol.
SAFETY ALERT SYMBOL
Be Prepared - Get to Know All Operating and Safety
Instructions.
This is the Safety Alert Symbol. Wherever it appears in
this manual or on safety signs on the machine you
should be alert to the potential for personal injury or
accidents. Always observe safety precautions and follow
recommended procedures.
CAUTION!
This word is used on safety messages and safety labels
and indicates potential of a hazardous situation that, if
not avoided, could result in minor or moderate injury. It
may also be used to alert against a generally unsafe
practice.
WARNING!
This word is used on safety messages and safety labels
and indicates potential of a hazardous situation that, if
not avoided, could result in serious injury or death. It
may also be used to alert against a highly unsafe
practice.
DANGER!
This word is used on safety messages and safety labels
and indicates an imminent hazard of a situation that, if
not avoided, is very likely to cause death or extremely
serious injury. It may also be used to alert against
equipment that may explode or detonate if handled or
treated carelessly.

9. SP000014
Page 9
Track Excavator Safety
Safety precautions are described in SAFETY from page -11
on.
DOOSAN cannot predict every circumstance that might
involve a potential hazard in operation and maintenance.
Therefore the safety messages in this manual and on the
machine may not include all possible safety precautions. If
any procedures or actions not specifically recommended or
allowed in this manual are used, you must be sure that you
and others can do such procedures and actions safely and
without damaging the machine. If you are unsure about the
safety of some procedures, contact a DOOSAN distributor.
DANGER!
This word is used on safety messages and safety labels
and indicates an imminent hazard of a situation that, if
not avoided, is very likely to cause death or extremely
serious injury. It may also be used to alert against
equipment that may explode or detonate if handled or
treated carelessly.

10. SP000014Track Excavator Safety
Page 10
GENERAL SAFETY
ESSENTIALS
Accessory Applications
The excavator has been primarily designed for moving earth
with a bucket. For use as a grapple or for other object
handling, contact DOOSAN for proper installation and
application. Lifting-work applications (unless restricted or
prohibited by local regulations) are permitted in approved lift
configuration, to rated capacity only, with no side-loading.
DO NOT use the machine for activities for which it was not
intended. DO NOT use the bucket for lifting work, unless lift
slings are used in the approved configuration.
Use of an accessory hydraulic hammer (breaker), work in
rough terrain, demolition applications or other hazardous
operation may require installation of additional protective
structures to safeguard the operator.
Lifting Capacity Rating Configuration
Lifting capacity ratings that are printed at the end of this
safety section are based on the machine being level, on a
firm supporting surface, with hooks and slings attached in
approved configuration. Loads must be balanced and
supported evenly. Use tag lines to keep the load steady if
wind conditions and large surface area are a problem. Work
crew hand signals, individual tasks and safe procedures
should all be universally understood before the lift is made.
IMPORTANT
Before using the excavator to make lifts check
municipal and regional regulations or statutes that could
apply. Governing ordinances may require that all heavy
lifting be done with single purpose equipment
specifically designed for making lifts, or other local
restrictions may apply. Making heavy lifts with a general
purpose excavator that can be used for digging, loading,
grading or other work may be expressly forbidden by a
regional injunction or other legal prohibition. Always
follow all of the other instructions, guidelines and
restrictions for Safe Lifting in the Operation and
Maintenance Manuals.

11. SP000915
Page 1
Swing Reduction Gear
SP000915
SWING REDUCTION GEARSP000915
Swing
Reduction
Gear
Edition 1

12. SP000915
Page 7
Swing Reduction Gear
GENERAL DESCRIPTION
Theory of Operation
The swing motor final drive is a two-stage planetary gearbox
with two planet gears, two sun gears and two-stage output
reduction. The planetary gear engages the ring gear. The
pinion gear is connected to the output shaft and spline.
The final drive reduces swing motor rpm in order to increase
swing motor output torque. The available maximum swing
speed provides a fast turning rate for efficient, rapid work
cycling with more than adequate power for good
acceleration.

13. SP000915Swing Reduction Gear
Page 8
Parts List
2
33
3
5
4
1
27
27
7
8
10
20
26
29
30
25
23
22
21
18 14
13
12
11
15
28
6
19
31
16
17
32
9
24
FG007053Figure 1

14. SP000915
Page 9
Swing Reduction Gear
Specifications
Reference
Number
Description
1 Casing
2 Drive Shaft
3 Plate
4 Spherical Roller Bearing
5 Cover Plate
6 Snap Ring
7 Oil Seal
8 Spherical Roller Bearing
9 Ring Gear
10 No. 2 Carrier
11 No. 2 Thrust Washer
12 No. 2 Planet Gear
13 No. 2 Bush
14 No. 2 Pin
15 Spring Pin
16 Hex Head Bolt
17 No. 3 Thrust Washer
18 No. 2 Sun Gear
19 Lock Pin
20 No. 1 Carrier
21 No. 1 Thrust Washer
22 No. 1 Planet Gear
23 No. 1 Pin Assembly
24 Socket Head Bolt
25 No. 1 Sun Gear
26 Snap Ring
27 Plug
28 Plug
29 Level Gauge Pipe
30 Level Gauge
31 Double Tap Washer
32 Pipe
33 Hex Head Bolt
Reference
Number
Description
Swing Reduction Gearbox Specification
Drive Type Two-stage Planetary Gear
Reduction Ratio 19.636
Maximum Output Speed 83.6 rpm
Maximum Output Torque
1,120 kg•m
(8,100 lb ft)
Weight
120 kg
(265 lb)
Pinion Gear Specification
Type Spur Gear
Gear P.C.D
156 mm
(6.14 in)
No. of Teeth 13
Module 12

15. SP000915
Page 11
Swing Reduction Gear
REMOVAL
1. Park on firm and level ground.
2. Lower front attachment (bucket) to ground.
3. Shut down engine.
4. Set safety lever on "RELEASED" position.
5. Turn starter switch to "I" (ON) position.
6. Fully stroke work levers (joysticks) in all directions to
relieve any pressure from accumulators.
7. Set safety lever on "LOCK" position.
8. Turn key to "O" (OFF) position and remove from starter
switch.
9. Hang a maintenance warning tag on controls.
10. Disconnect negative (-) battery cable leading to frame
from battery.
11. Tag and disconnect hoses from swing motor (1, Figure
3). Plug and cap hoses and ports to prevent
contamination from entering hydraulic system or
component.
12. Assemble drain hose (3, Figure 3) to drain valve (8)
and drain oil from reduction gearbox (5, Figure 3).
13. Remove drain hose (3, Figure 3) from drain valve (8)
and disconnect hose (2, Figure 3) from reduction
gearbox (5).
14. Disconnect grease lubrication line (7, Figure 3) from
reduction gearbox (5).
15. Remove eleven bolts and washers (4, Figure 3) holding
swing reduction gearbox (5) to frame.
16. Using a suitable lifting device, sling swing motor (1,
Figure 3) and remove swing motor and reduction
gearbox (5) as an assembly from unit.
NOTE: There is a alignment pin (6, Figure 3), on
reduction gearbox flange.
O I
FG007720
WARNING
DON'T TOUCH WHEN
PERFORMING INSPECTION
OR MAINTENANCE
Figure 2
WARNING!
If engine must be running while performing
maintenance, always use extreme caution. Always
have one person in cab at all times. Never leave
cab with engine running.
FG007055
1
5
3
7
8
2
4
6
Figure 3

16. SP000915Swing Reduction Gear
Page 12
DISASSEMBLY
1. Remove bolts and motor from swing reduction case.
2. Remove No. 1 sun gear from No. 1 carrier.
IMPORTANT
Select a clean place.
Spread a rubber mat or cloth on top of the overhaul
workbench to prevent parts from being damaged.
Figure 4
CAUTION!
The motor should be separated without damage or
any foreign substance.
Figure 5
CAUTION!
Care should be taken not to damage mounting
surface of motor. Carefully remove all gasket
material from mounting surfaces.
Figure 6
CAUTION!
Care should be taken not to damage teeth of No. 1
sun gear.

17. SP000915
Page 13
Swing Reduction Gear
3. Remove No. 1 carrier.
4. Remove washer and No. 2 sun gear.
Figure 7
Figure 8
Figure 9
CAUTION!
Care should be taken not to damage teeth of No. 2
sun gear.

18. SP000915Swing Reduction Gear
Page 14
5. Remove bolt in No. 2 carrier.
6. Install eye bolts in No. 2 carrier and remove it from
ring gear.
Figure 10
Figure 11
CAUTION!
Care should be taken not to damage teeth of No. 2
carrier and ring gear.
Figure 12

19. SP000915
Page 15
Swing Reduction Gear
7. Install eye bolts in ring gear and remove it.
Figure 13
Figure 14
Figure 15
CAUTION!
Care should be taken not to damage mounting
surfaces of ring gear and case. Carefully remove all
gasket material from mounting surfaces.

20. SP000915Swing Reduction Gear
Page 16
8. Use a rollover machine to turn assembly over.
9. Remove cover plate.
Figure 16
Figure 17
Figure 18
Figure 19

21. SP000915
Page 17
Swing Reduction Gear
10. Use a rollover machine to turn case over and place a
jig on drive shaft. Use a press to remove drive shaft
from case.
11. Remove bearing from case.
Figure 20
CAUTION!
Care should be taken not to have drive shaft drop
to floor when it is pressed out of case.
Figure 21
Figure 22

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23. SP000915Swing Reduction Gear
Page 18
12. Put drive shaft in press, and remove bearing and
spacer.
CLEANING AND INSPECTION
(WEAR LIMITS AND
TOLERANCES)
For general cleaning and inspection procedures, refer to
"General Maintenance Procedures" section.
Figure 23
Figure 24

24. SP000915
Page 19
Swing Reduction Gear
REASSEMBLY
Shaft and S/R Bearing Heat-fit
1. To cleaning shaft, remove any remnants of
anticorrosion liquid applied on shaft and remove all of
foreign substances using an air gun.
2. Insert spacer on cleaned shaft as shown in figure
below and heat bearing on a special heater.
Figure 25
Figure 26

25. SP000915Swing Reduction Gear
Page 20
3. Stop heating when bearing temperature is between 90°
- 100°C (194° - 212°F) and insert it on shaft, holding it
with both hands to keep it level. Insert it slowly first by
4 - 5 mm (0.16 - 0.29 in) for bearing to seat itself and
then push it hard that it contacts to spacer assembled
in shaft completely.
4. After bearing assembly is completed, leave it air cool
for 1 - 2 hours.
Assembly of Carrier Subassemblies
Cleaning Carrier
Put carrier, to whose corners grinding was made to remove
all foreign substances like burr, on steam washer if there
remain any foreign substance and put it on assembly die.
Cleaning Planet Gear
Check if planet gears are washed cleanly and got imprinted
and put it on assembly die.
Figure 27
Figure 28